Breast cancer is the second leading cause of death of women in the world. The early detection gives a
better chance to cure it. Physicians diagnose breast tumors by analyzing the characteristics of the lesion in
ultrasound images. Shape data, provi
ded by a tumor contour, is important to physicians in making
diagnostic decisions. However, due to the increasing use of technology in medicine, a computer aided
detection systems (CAD) have been built to help the expert. This research focuses on using a level-set
method as an effective lesion segmentation method for breast ultrasound images. By applying non-local
means filter on image, the unwanted speckle noise will be removed and the image's important details will
be preserved. Then the initial contours are sketched using the GUI in order to apply level-set method
which delineates the contour of the lesion in breast ultrasound image. The proposed method was found to
determine the breast tumor contours that are very similar to manual-sketched contours (about 96%).
